ABSTRACT Pneumonia and its complication of post-discharge disability are increasingly common and survivable. Treatment has had important advances in the last decade. Yet it has also become clear that pneumonia is often life-altering for patients who survive. Many survivors develop new long-term disability and cognitive impairment, at least among older survivors. Unfortunately, we have few interventions to improve these problems. While we have learned that post-discharge disability after pneumonia is an important public health problem, we have little empirical data on the trajectories of recovery for patients. We propose to address this problem through a collaboration from two research teams (the University of Michigan, including the Institute for Social Research, and the Kaiser Permanente Division of Research's Systems Research Initiative) and do so in a community setting. Kaiser Permanente Northern California is an integrated healthcare delivery system with comprehensive electronic records. Starting with an explicit goal of defining patient trajectories, we will follow a community-based inception cohort of 1,232 patients with pneumonia with 868 completing follow up. This cohort will be interviewed within 1 week of hospital discharge and again at 1, 3, 4, 6, 9, and 12 months after hospital discharge with a focused phone survey to assess post-discharge disability. Frequent brief interviews will provide the first disease-specific trajectory measurements for patients with the common condition of pneumonia. Our Aims are: Aim 1: We will quantify archetypical trajectories of recovery or disability in the year after pneumonia using advanced statistical methods to understand what are the common trajectories, and what modifies those trajectories?characteristics of the patient, of the pneumonia hospitalization, and recurrent hospitalizations. Aim 2: We will identify testable `Recipes for Success' to understand how do some patients beat the odds and experience a substantially faster recovery using detailed in person testing and interviews with patients identified as doing far better than would have been expected based on their hospitalizations and prior life. This proposal is significant in that it addresses a large but understudied public health problem and will inform translational clinical trials, basic biological research, clinical practice, and public policy about readmissions. It is innovative in its conceptualization of recovery from pneumonia as a trajectory over time requiring high- resolution quantitative mapping with frequent surveys in order to be appropriately understood. Further, it innovatively combines detailed physiologic and health services data with repeated surveys to map the patient experience; uses innovative statistical methods to quantitatively define trajectories of recovery; focuses on the full age-range of a diverse, community-based sample; and unites a multi-disciplinary team's varied expertise.